Astroblog

Obscured by Clouds. The rough and ready blog of a cloud benighted biologist and amateur astronomer. Astroblog will cover my interests in astronomy, biology and Life, the Universe and Everything.

Tuesday, August 31, 2010

Southern Skywatch September 2010 edition is now up!

The evening sky facing west in Melbourne on September 11 at 7:00 pm AEST showing Venus, Mars and Spica close together. (similar views will be seen from other cities at the equivalent local time eg 7:00 pm ACST Adelaide).

The Sky This Week - Thursday September 2 to Thursday September 9

The New Moon is Wednesday September 8. Mars, Venus and Spica form a triangle in the sky. Mars closes in on the bright star Spica. Jupiter can be seen in the east in the late evening. Jupiter and Uranus are seen together in binoculars

Evening sky looking East as seen from Adelaide at 8:30 pm on Thursday September 9 showing Jupiter close to Uranus. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

The New Moon is Wednesday September 8.

Jupiter rises before midnight, and can be readily seen from about 8 pm local time just above the eastern horizon. At the beginning of the week you can see Jupiter rising in the east while Venus is setting in the west.

Jupiter and Uranus are close together and can be seen near each other in a pair of binoculars. Uranus is the brightest object within a binocular field north of Jupiter, and is in fact bright enough to be (just) seen with the unaided eye under dark sky conditions. A binocular spotters map is here. During the week Jupiter and Uranus come closer.

Jupiter is still visible in the early morning in the north-western sky as the brightest object low above the horizon.

Evening sky looking North-west showing Venus, Mars, Spica and Saturn at 6:30 pm local time on Monday September 6. Click to embiggen.

Bright white Venus is readily visible above the western horizon from half an hour after Sunset, (even before) until past the end of twilight (about an hour and a half after sunset).

Venus is in Virgo the Virgin, close to Mars and the bright star Spica (alpha Virginis) forming a triangle. Venus rises higher during the week, and Mars closes in on Spica, coming closest on the 6th. Saturn is low in the twilight, just above the horizon.

Mars is distinguishable by its reddish colouring.

Saturn is visible low in the western evening twilight sky as the bright yellow object well below Venus and Mars. During the week Saturn comes closer to the horizon. Telescopic observation of the ringed world is now extremely difficult as Saturn sets earlier. On Thursday September 9 the thin crescent moon will be close to Saturn, but you will need a clear, level horizon to see them together.

If you don't have a telescope, now is a good time to visit one of your local astronomical societies open nights or the local planetariums. Jupiter is well worth telescopic observation, and even in binoculars its Galilean moons are easily seen.

Star Party in Memory of Jeff Medkeff

Fraser Cain (originator of the Carnival of Space) and Pamela Gay are organising a star party in memory of Jeff Medkeff on September 2nd, in Atlanta (USA). Unfortunately it is sold out now, but you can get on the waiting list. Find details here.

Sunday, August 29, 2010

Mobile Phone Moon again (and Jupiter)

Well, reader Cormac Scanlon took this image of the Moon through binoculars using a mobile phone. The major proble is that the moon is over exposed when Ii try it, and using various filtering materials didn't help.

Cormac has a Nokia n79 phone, and he was able to use the customised 'scene mode'; here are his settings:

flash mode --> off

white balance --> sunny

exposure compensation --> -2.0

colour tone --> normal

light sensititvity --> low

sharpness & contrast --> normal.

I can do something similar on my phone, so I'm going to try as soon as possible. Thanks for the heads up Cormac!

Cormac also got a shot of Jupiter through his binoculars, this time setting sensitivity to high. He said that getting anything other than a semar was hard, I can believe that. Here's hoping Cormac sends us more astronomical images with his mobile phone.

Carnival of Space #168 is here.

Carnival of Space 168 is now up at Weird Sciences. There's the Trojan Asteroid of Neptune, the Incredible Shrinking Moon, musings on faster than light travel, Io's true colours and much, much more. Speed on over and have a read!

There is an embarrassing tale associated with this image though (scroll down below video).

Comet Al asked the stereohunter group if a comet he found in the H1 imager was likely to 2P/Encke. Now, a while back I had entered the orbit of 2P/Encke in Celestia, in order to see if it did go through either the H1A or H1B imagers, using the latest JPL Horizons orbital data (and double checking the positions in SkyMap). I ran the orbits forwards a fair way, but they didn't come into the H1A FOV. So I told Comet Al, no, it's unlikley, but I would recheck with the latest orbital data.

So I generated an ephemeris to cover the date that Comet Al observed his comet, generated positions in SkyMap and checked against the FOV of the H1A imager and nope, it wasn't in the FOV. Very suspiciously it was right next to where Comer Al's comet appeared, but I emailed back saying "nope, not Encke".

Shortly after, when everyone else was emailing "Yes, it's Encke" did I realise I misread the dates on the impage time stamps, and had generated positions of the 20th, not the 23rd, when the images were actually taken.

Friday, August 27, 2010

Comet 2P/Encke meets the Sombreo Galaxy

Comet Encke as seen (or rather not seen with the unaided eye) from Adelaide on the evening of 30th August, at 19:30 ACST. Similar views will be seen at equivalent local times elsewhere in Australia.

Comet 2P/Encke has now faded below binocular reach. However, for those of you with telescopes, on Monday August 30th Comet Encke will be under a degree from the Sombreo Galaxy.

The comet will be reasonably high, around 16 degrees, from the horizon when astronomical twilight sets in, but with the separtaion so wide, you will need something like a 20mm objective to get both the comet and the galaxy within the same filed of view. they won't be spectacular, but interesting all the same.

Encke and the Sombreo galaxy as they might appear in a 6" scope with a 20 mm eyepiece.

The Sky This Week - Thursday August 26 to Thursday September 2

The Last Quarter Moon is Thursday September 2. Mars Venus and Saturn form an elongated triangle. Venus closes in on the bright star Spica. Mercury is lost from view. Comet Encke may be visible in binoculars. Jupiter can be seen in the east in the late evening.

Evening sky looking East as seen from Adelaide at 10:00 pm on Friday August 27 showing Jupiter close to the Moon. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

The Last Quarter Moon is Thursday September 2.

Jupiter rises before midnight, and can be readily seen from about 9 pm local time just above the eastern horizon. By the end of the week you can see Jupiter rising in the east while Venus is setting in the west. On the 26th and 27th Jupiter is close to the Moon. You may be able to use the Moon to guide you to see Jupiter in the daylight, but Jupiter and the Moon set soon after Sunrise.

Jupiter is still visible in the north-western sky as the brightest object low in the early morning. Jupiter and Uranus are close together and can be seen near each other in a pair of binoculars. Uranus is the brightest object within a binocular field north of Jupiter.

Evening sky looking North-west showing Venus, Mars, Saturn and Comet Encke at 6:30 pm local time on Tuesday August 31. Click to embiggen.

Mercury can be seen above the western horizon from half an hour after sunset. By the end of the week, it is lost in the twilight.

Comet 2P Encke may be visible in binoculars at the beginning of the week, but is rapidly lost to view. Those with telescopes may see Encke near the Sombreo galaxy on the 30th.

Bright white Venus is readily visible above the western horizon from half an hour after Sunset, (even before) until past the end of twilight (about an hour and a half after sunset). Venus is now in Virgo the Virgin, close to Mars with Saturn below forming a long, narrow triangle. Venus closes in on the bright star Spica, alpha Virginis and is closest on the 31st. During the week Mars also comes closer to Spica.

In the evening Mars can be seen low in the north-western sky. Mars is below Venus, at the beginning of the week. Mars is distinguishable by its reddish colouring.

Saturn is visible low in the western evening sky as the bright yellow object below Venus and Mars. During the week Saturn draws further apart from the pair. Telescopic observation of the ringed world is now difficult as Saturn sets earlier.

Monday, August 23, 2010

My Seminar With Ian Plimer

Professor Ian Plimer, one of Australia’s leading Climate Change Inactivists, gave a talk at my School today. Professor Plimer has written a book about global warming, “Heaven and Earth”, which has an impressive list of inaccuracies and errors. I found out about the talk late, so I had very little time to get my thoughts together before the talk started.

Professor Plimer is a very good and charming speaker, but he didn’t make it clear where he was going in his talk. He gave a grand sweep of geological time, but even I who is a geological time geek, found it difficult to follow which way he was going. He was trying to show that temperatures and climate had varied a lot in the past and that CO2 was not the main driver, but because he hadn’t really set up the issue of modern global warming, it was unclear where he was heading.

In fact, he managed to talk about climate change without showing contemporary graphs of surface temperature change (with two exceptions which I’ll talk about later). He spent a long time talking about how surface temperature stations were bad (they are not; again, this was without showing the temperature record itself), then showing the satellite record at a scale where it was hard to see what was going on and claiming that a) satellites were more accurate (they have different problems) and b) temperatures had not changed (but satellite measurements confirm land surface measurements). He flashed up a small segment of the land surface record that was dipping while showing CO2 going up, but if he had shown the full CO2 /temperature record the picture would have been entirely different.

Image credit Real Climate. Showing how the satellite record of temperatures follows the surface temperatures.

The main thing about the talk was it's overall contradiction, approximately half the talk tried to show temperatures weren't changing, and the other half tired to show that temperatures were changing and that the Sun (or cosmic rays or something; anything but people) was responsible.

When the Question time came I made a mistake, I should have gone for the inherent contradictions in the talk (If increasing sunspots track increasing temperature, doesn't that contradict your statement that global temperatures aren't rising). Instead I pointed out that the sunspot graph was wrong, and there was no correlation between sunspots and temperature in the contemporary period. Professor Plimer attentatively wrote down the details, perhaps in his next talk there will be one less error.

Unfortunately, I didn't get a chance to talk to Professor Plimer after, I had to rush off to run a workshop for the second years. However, if Barry Brook can't convince Professor Plimer, I have no chance of influencing him.

Another Asteroid/Comet Impact on Jupiter

A Japanese amateur astronomer imaging Jupiter on August 20 UT has recorded a flash which may be an impact on the giant planet. The report is here, and you can see a video of the impact flash here. With the 19 July 2009 and 2010 June impacts, it looks like things hitting Jupiter might be more common than we thought.

Sunday, August 22, 2010

Venus with Angel (but no comet)

Venus (the bright dot between the two flagpoles upper centre of the image), above the Time-ball tower and the Angle of Remembrance at Semaphore. This was taken with my mobile phone (click to embiggen)

EldestOne and I were out getting take-away noodles and DVD's to avoid the incessant election natter on TV. Of course, this was the first night in ages it wasn't raining, and I missed an opportunity to look for comet Encke.

A Ceiling Full of Sky

It's an astronomical theme, zodiacal figures surround the central figures (you really need to embiggen them to get a good view) which are .... well, I don't actually know. I think that it's the Moon attended by Venus, but I could be wrong. There wasn't any information in the entrance way itself about the ceiling (that I saw), and there seems to be nothing online.

It didn't help that most of the University was destroyed in 1801 by English bombardment, so the information of the ceiling may have been lost.

Carnival of Space #167 is here.

Carnival of Space 167 is now up at the Space Tweeps Society. This society is devoted to tweeting information about space, so every carnival entry is associated with a tweet. There's nano satellites, planetary geomorphology, space models, hyperluminal travel and much, much more. Zip on over and have a read.

Thursday, August 19, 2010

A Nice View of Moon and Planets

Correspondent Alan Garde took this lovely image of the line-up of Moon, Mercury, Saturn, Venus and Mars on Wednesday August 11 (click to embiggen). This was taken from Eleebana NSW, near Lake Macquarie. Alan liked the way the Moon was placed under the tree, and I agree with him. Alan says

"The picture wasn’t exposed as well as it might have been. The instrument of phenomenal dynamic range that is our eye tricks us most of the time."

UPDATE: Alan says that the credit for the photograph goes to his friend friend Stephen Palmer.

Alan also says he clearly and regularly picked out Venus in the daylight last Sunday lunchtime, his son said he could see it though.

Wednesday, August 18, 2010

Mercury, Crescent Moon and a Triangle in the Sky

Long time contributor Chirs Wyatt had cloud and rain on the 13th, but was able to get off the shot you see to the left (click to embiggen, you will not regret it). He's captured the Earthshine on the Moon wonderfully, as well as the glowing triangle and Mercury.

Tuesday, August 17, 2010

Start Looking for Comet 2P/Encke Tonight!

Overlay showing the pasth of Comet 2P/Encke between the 17th and 20th of August, 2010. The veiw is at 18:41 local (Australian) time. The stars change position as well, setting earlier each successive night.

Tonight (17th) and the 18th, 19th and 20th of August Comet Encke is within a binocular field of Mercury, being closest on the 19th. You will need binoculars and a clear horizon to see it, but it should be worth the effort.

Printable greyscale high resolution view of the comet and Mercury, the circle shows the approximate filed of view of 10x50 binoculars. Use a red light if reading this while huting the comet, and allow your eyes to adjust to the dark

The Sky This Week - Thursday August 19 to Thursday August 26

The Full Moon is Wednesday August 25. Four of the 5 classic planets are visible together in the early evening sky. Mars Venus and Saturn form a triangle, with Mars and Venus closest on the 19th. Mercury is below these three. Comet Encke may be visible in binoculars near Mercury on the 19th. Jupiter can be seen in the east in the late evening.

Evening sky looking North-west showing Mercury,Venus, Mars, Saturn and Comet Encke at 6:30 pm local time on Thursday August 19. Click to embiggen.

The Full Moon is Wednesday August 25.

Jupiter rises before midnight, and can be readily seen from about 9 pm local time just above the eastern horizon. By the end of the week you can see Jupiter rising in the east while Venus is setting in the west.

Jupiter is still visible in the north-western sky as the brightest object low in the early morning. Jupiter and Uranus are close together and can be seen near each other in a pair of binoculars. Uranus is the brightest object within a binocular field north of Jupiter.

Evening sky looking North-west as seen from Adelaide at 6:30 pm on Thursday August 26 showing Mercury below the massing of the Spica, Venus, Saturn, and Mars. Comet Encke is not far from Saturn. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

Four of the five classic planets can be seen together in the early evening sky making fantastic patterns.

Mercury can be seen above the western horizon from half an hour after sunset. It is still quite easy to see, just below the massing of Venus, Mars and Saturn. On the 19th Mercury and the comet 2P/Encke are a degree apart, and Encke should be reasonably visible in binoculars. On the 20th, Mercury and Comet Encke within a binocular field of each other. The Comet is at at magnitude 7 and may be a little difficult to spot, it will look like a fuzzy dot. Over the week Encke climbs higher in the evening sky, but fades rapidly, and may be lost to binoculars by the 25th

Bright white Venus is readily visible above the western horizon from half an hour after Sunset, (even before) until past the end of twilight (about an hour and a half after sunset). Venus is now in Virgo the Virgin, close to Mars and Saturn. On Thursday August 19 Venus, is at its closest to Mars, forming a long narrow triangle with Saturn. During the week Mars and Venus close in on the bright star Spica.

In the evening Mars can be seen low in the north-western sky. Mars is beside Venus, at the beginning of the week. Mars is distinguishable by its reddish colouring.

Saturn is easily visible in the western evening sky as the bright yellow object below Venus and Mars. During the week Saturn draws further apart from the pair. Telescopic observation of the ringed world is now difficult as Saturn sets earlier.

Monday, August 16, 2010

Live Blogging the Naked Scietists

Here I am live blogging a talk by the founder of the Naked Scientists, and I didn't bring my camera!

Chris Smith starts with a humorous slide show. Fundamental rule, the internet will take what you put up and spit it out in ways you don't want. Discusses the role of humour in gaining attention and getting people engaged.

Podcasts and radio broadcasts, verbal, not visual, sometimes need visuals so do Kitchen science: experiment done alongside broadcasts and people phone up with results; reinforce messages. Made a chocolate teapot, need 1 inch thick chocolate to withstand boiling water, did brew a decent cuppa with chocolate teapot.

How fat do you have to be to stop a bullet. 76 cm of fat gut will stop a bullet. (video of ball bearing shout out via helium powered gun, going through tube of gelatin).

Sneezes travel at 108 Km/hr. Made use of estimation to get people engaged and thinking.

Quote: "People say scientists are humorless, but anyone who has looked at a chemistry encyclopedia will know that this is not true" Used arsoles as example, and moronic acid (actually pistacio resin, used to date pottery). Lots of other funny names (too rude to write here). B13 (orotic acid, is also known as erotic acid because so many people misspell it).

Chris now asks for questions: Asked to comment on intelligent Design, uses Ca2SbMg4FeBe2Si4O2O as his reply, then explains difference between UK (state wide curriculum) vs US (local board control) should biology be taught in RE? Why should RE teachers teach biology. "Can argue intelligently with creationists, but it takes 10 years" (paraphrase).

Chris is an accomodationist :-)

Lots of creationism questions (talks about Lenski), now on to charter schools.

I get at ask a question, I ask how he chooses stories. Chris says he takes home 30 papers that have just been published, and looks at them to see if they are a) interesting, b) of general interest, c) can be explained simply d) can be done on radio. Usually choose 5 stories, then write up a couple of paragraphs on each. Send to Radio National, they choose enough stories for 7-8 minutes (not even UK does this, Yay Australia!). Then on the day of the Naked Scientists broadcast, meet with collaborators, choose from all stories written. Also get an interview from one of the authors of chosen papers.

Are scientists bad communicators? Chris feels scientists get a bad rap about communication, more a reflection of what editors are interested in. How can scientists communicate their love of science better? Youtube type videos?(use humor, educate by subversion)

Naked Scientists scrapbooks. Videos with drawings to get kids intrigued. Most work done with auido, but use live sketches to capture imagination. Cover lots of concepts in a short time. (eg, why don't birds is sitting on pwerlines get electrocuted, covers circuits, heart structure, brain oxygen requirements, electrical theory. not live yet). Designed for Youtube propagation.

What gave Chris the inspiration to jump from science to science communication: Chris says "i'm a pathological learner" did medicine, fascinated by neuroscience, added in PhD looked at designing viruses to deliver genes to the central nervous system (very cool work!). Loved learning about sciecne, got involved in Cambridge Science festival, over a week doors opened to public and all free (lectures, hands on demonstrations etc,). Used large firecracker in bin, destroyed bin and made everyone jump, fire alarms went off, but demonstrated nerve conduction velocity. "Edutainment" making science fun as well as enlightening. Then radio interviewer got them on show, and it snowballed from there. Asked for grant to get funding to buy air time for a weekly science show, GOT funding, radio show signed them up. Then radio show asked them to carry on. Did this in middle of PhD. Though of funny name Bought domain name of Naked Scientist, one of worlds first science podcasts, and BBC heard it and took them on (website 3 million hits per year, podcast in top 10 in itunes downloads!) So popular had trouble find sponsor for downloading 15 TERABYTES of data!!!). Did manage to break this server!

Did PhD, did medical rounds, working doctor, has done clinical virology training .... while still doing Naked Scientists!! (joke, Chis created multimedia empire in less time then it took to pass his virology exams, proving the exams are hard).

Question: do you run out of ideas! No, still have new ideas. Naked Engineering coming soon!

What was the best experiment you've ever done? Chocolate teapot, How fat do you have to be to be to stop a bullet, Volcano Bombs (wallpaper past dissolved in fizzy drinks, mess is devastating),

Question has there been anything that you wanted to talk about but was too complicated: Quantum mechanics (proton is 4% smaller than we though, explaining this difficult. Made Muonic hydrogen, muons instad of electrons, Muons orbit closer to the protons, by recording energy given off muons being excited, specific energy means that protons must be smaller.)

What was surprising about human genome project? How few genes we have. Epigenetics.

What would you say to Australian leaders to bolster science in the community. Politicians like dollar signs. Science makes technology, technology makes money.

Saturday, August 14, 2010

Ask The Naked Scientist! - National Science Week 16 August

As part of National Science Week, Ask The Naked Scientist is happening on Monday, August 16 at 7.00pm in the Napier Theatre, University of Adelaide, North Terrace, Adelaide (K12 on this printable Map). Entry is free and no bookings are required.

This is an audience-interactive science question and answer show. Taking questions from the public on any science-related topic, Dr Chris Smith of Cambridge University responds in innovative, informative – and sometimes hilarious – ways.

A medical doctor and clinical lecturer in virology at Cambridge University, Chris Smith founded The Naked Scientists, an award-winning radio program on the BBC (and one of the world’s most down-loaded podcasts) that aims to strip science down to its bare essentials. Chris is one of the international guests touring the country in National Science Week.

When I saw these colourful splashes appearing on the floor of the Metro in Kongens Nytorv (which I always mispronounced as Koenigs, well Kongen does mean King as does Koenig), I was entranced, and started looking about for the door or window that had accidentally acted as a prism.....and found the deliberately placed prisms.

The light wells in the roof of the metro have a series of prisims specifically to catch light and send rainbows cascading down on the metro travellers. How could you not love a city like that!

Left image another rainbow in the stairwell, right image, the spiral of prisms in the light well.

Putting Comet 2P/Encke in Stellarium

Comet 2P/Encke is within a binocular field of Mercury on the 17th, 18th and 19th of August. Shown here is the view on the 18th. The comet is fainter than magnitude 6, so you will only see it in binoculars (and even then as a fuzzy dot).

In about a weeks time Comet 2P/Encke will be visible in the southern hemisphere in western skies, sadly it will be binocular visible only, but it does come close to Mercury. As I've mentioned several times before, you can add new objects, such as comets and asteroids, to Celestia and Stellarium. If you want to follow 2P/Encke in stellarium or Celestia. I've made up a Stellarium add-on and a Celestia .ssc file for 2P Encke. (scroll down to the bottom of the second image for the add-on.)

The approximate view seen through a pair of 10x50 binoculars on 18th August, centred on Mercury. ENcke might a a discernible tail, depending on how dark the sky is where you are.

The stellarium file for Encke (works in versions 10.x and 9.x); just copy and paste the section below at the end of the system.ini file. When you run Stellarium, you will have to turn planet hints on in the configuration menu if they are not already on. you will also have to adjust the magnitude slider so the circle will appear in Version 10.x. For Celestia the .ssc file goes into the extras folder. Note that the albedo and diamtere are wrong in the Stellarium add-on, but it doesn't give me the right magnitude if I use the real values.

Thursday, August 12, 2010

Why Yes, it was Cloudy.

So no Mercury and the Moon for me. Have a picture from a couple of days ago instead. Click to embiggen. Mercury is just above the telegraph pole, Venus, Mars and Saturn are obvious and the bright streak is an artefact from the sodium light in the street.

Wednesday, August 11, 2010

The Son of the Zombie Mars Hoax that will not Die

Sheesh is it that time of year again? The Mars hoax is circulating once more. No, Mars will not be as big as the full Moon, there will be no double Moon in the sky. In fact, Mars is very, very far from opposition and is almost at its smallest (it won't be at opposition again until 2012). However, on August 27, in the early evening Mars, Venus and Spica from a nice triangle. For an overveiw of what the Mars hoax is and why it is so wrong, see the Return of the Zombie Mars Hoax that will not Die.

Carnival of Space #166 is here.

Carnival of Space #166 is now up at the Gish Bar Times. There is finding true north, the Perseid meteor shower, X-ray astronomy at solar maximum, memories of Aurora Borealis, how much Io smells and much, much more. Head on over now for a good read!

Tuesday, August 10, 2010

Perseid Meteor Shower - morning August 13, 2010

Northern sky as seen from Darwin on the morning of August 13 at 4:00 am. Click to embiggen.

The Perseid Meteor Shower peaks on the morning of Thursday August 13. Despite this being a quite reasonable meteor shower, and probably in outburst this year, for most of Australia, the radiant is below the horizon, and only the very occasional meteor shooting up from the northern horizon will be seen.

Anyone south of Brisbane will see only the occasional meteor, say maybe one or two per hour, the further north of Brisbane you are, the more meteors you will see.

You can check predictions for your local area at the NASA meteor flux estimator (choose 7 Perseids and 12-13 August 2010). People around Alice Springs and Darwin have the best chance of seeing meteors, possibly as many as one every 3 minutes. With the Moon in the evening sky, this should be a good time to see the Perseids.

To see the meteors, you will need to be up around 3:00 am local time on the 13th (yes, a really horrible hour of the morning), with best views 4:00 am-5:30 am. The meteor shower will be located due North, with the radiant just above the northern horizon. You can follow the Perseids at the International Meteor Organisations live website. Cloud cover predictions can be found at SkippySky.

A nice video of a Perseid fireball from this year is here and another one here. And here are some images from Singapore.

Note, those of you who have Stellarium, the meteor shower you see when you turn on the Meteor button in the star and planet visibility dialogue is the Leonids, the radiant is only correct for 18 November, it only coincidentally is vaguely in the area of the Perseids.

The Sky This Week - Thursday August 12 to Thursday August 19

The First Quarter Moon is Tuesday August 17. Four of the 5 classic planets are visible together in the early evening sky. Mercury is prominent below these planets and is close to the crescent Moon on the 12th. Perseid meteor shower morning of 13th. The crescent Moon joins the triad of Venus, Mars and Saturn on the 13th. Comet Encke may be visible in binoculars near Mercury by the 17th.

Evening sky looking North-west showing Mercury,Venus, Mars, Saturn and the crescent Moon at 7:00 pm local time on Thursday August 12. Click to embiggen.

The First Quarter Moon is Tuesday August 17. on the 12th the Moon visits Mercury, on the 13th it visits Venus, Saturn and Mars, on the 14th it is close to the star Spica and on the 17th it is in the head of Scorpius the Scorpion.

Jupiter rises before midnight, and can be readily seen from about 10 pm local time just above the eastern horizon.

Jupiter is still visible in the north-western sky as the brightest object low in the early morning. Jupiter and Uranus are close together and can be seen near each other in a pair of binoculars. Uranus is the brightest object within a binocular field north of Jupiter.

Evening sky looking North-west as seen from Adelaide at 7:00 pm on Friday August 13 showing Mercury below the massing of the Crescent Moon, Venus, Saturn, and Mars. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

Four of the five classic planets can be seen together in the early evening sky making fantastic patterns.

Mercury can be seen above the western horizon from half an hour after sunset at the beginning of the week. It is now quite easy to see, just below the massing of Venus, Mars and Saturn. On the 12th the thin crescent Moon is not far from Mercury. At the end of the week Mercury and the comet 2P/Encke are within a binocular field of each other, but at magnitude 7 the comet may be difficult to spot low in the evening sky.

Bright white Venus is readily visible above the western horizon from half an hour after Sunset, (even before) until past the end of twilight (about an hour and a half after sunset). Venus is now in Virgo the Virgin, close to Mars and Saturn. On Friday August 13 Venus, Saturn, Mars and the crescent Moon are close together. During the week Venus comes closer to Mars and further form Saturn. By the end of the week Mars and Venus are close, and both are closing in on the bright star Spica.

In the evening Mars can be seen low in the north-western sky. Mars is above Venus, at the beginning of the week. Mars is distinguishable by its reddish colouring.

Saturn is easily visible in the western evening sky as the bright yellow object close to Venus. During the week Saturn and Venus draw apart. Telescopic observation of the ringed world is now difficult as Saturn sets earlier.

Monday, August 09, 2010

A Paper on Fructose and Cancer, it doesn't mean what you think it means

Over at Respectful Insolence Orac has discussed the misrepresentation of a study about the effect of fructose on pancreatic cancer. This post is a slightly expanded version of that comment, with some added diagrams and a bit more on fructose concentrations. The point is still that the press release (that limiting fructose intake may disrupt cancer growth), and some of the conclusions of the paper, are not justifyable from the data.

First, a little background. Sugar to most people is sucrose, or cane sugar. But actually "sugar" covers a large number of similar chemical compounds. Ones commonly encountered apart from sucrose include glucose and fructose (also known as fruit sugar as it is found in high concentrations in fruit, it is also found in honey). Indeed sucrose is glucose and fructose linked by a chemical bond. When you eat sucrose, enzymes in your gastrointestinal tract break it down into glucose and fructose, which are then absorbed (your body can absorb intact sucrose).

There is some concern that consumption of high levels of fructose may have negative health consequences above that of simply consuming more calories. People in the United States are particularly concerned as many of their soft drinks and foods are sweetened with High Fructose Corn Syrup (HFCS), as opposed to sucrose in most of the rest of the world (like Australia, where sugar cane fields are part of the national psyche). It should be pointed out that the proportion of fructose in honey is about the same as that in HFCS and some fruits (eg apples and pears) have significantly more. However, the large amount of extra sugar added to processed foods and soft drinks means we are be exposed to much higher concentrations of fructose (and glucose) than we would eating a diet of fresh fruit and vegetables.

Now in the paper there are two sets of results, one set on cancer cell proliferation, and one set on metabolism (seeing whether metabolic pathways involved in cancer growth were selectively activated by fructose). The authors show reasonably convincingly that fructose is preferentially metabolised to nucleic acids in pancreatic cancer cells, pancreatic cell models and hepatic cancer cells (with some caveats I will cover later[1]). However, what they say about the rate of cancer proliferation is almost, but not completely, dead wrong.

The first important thing to note is that when they did the proliferation assays, they compared the results to cells cultured in 10% Foetal Bovine Serum alone - which contained *0.4 mmol/L glucose*[2] (FBS in the figure, open bar, the black bar is complete medium with 10% FCS and 18mmol/L gulcose) . This means at the lowest concentrations of additional sugar, they are comparing 400µM glucose + 5.5µM fructose vs 405.5µM glucose. Which kind of messes up their interpretation.

Looking at the graph (note the red line showing basal growth, and the error bars) Generally, glucose and fructose are the same...they don't do anything above and beyond the Foetal Bovine Serum control. Only in MiaPaCa-2's, HPAF and, possibly, HPDR6 do you see proliferation which MAY be statistically significant from the baseline proliferation at the highest concentrations used (400µM glucose + 5500µM fructose vs 5900µM glucose, they look higher, but the error bars are significantly bigger too). An important caveat is that for the MiaPaCa-2 cells, when proliferation was remeasured using a different assay (BrDU incorporation), fructose basically did nothing. So any apparent increase in proliferation may just be assay variation.

It's a bit hard to clearly work out what data points are statistically significant, if any, as their statistics are borked, badly borked. The legend to Figure 1 says "P = not significant, fructose versus glucose or normal medium (NM)." Which if correct, means that the proliferation rates at 5.5µM added sugar (glucose of fructose) is no different from the 18 mM glucose normal medium values, which makes their data uninterpretable (see Figure 1B and C particularly). No other stats tests on the proliferation data are presented anywhere.

So we should reformulate the statement of the abstract as "In some cancer cell line, 5 mM fructose and 5mM glucose might cause the same amount of proliferation above that found with 0.4 mmol/L glucose, if we could statistically distinguish them from the control" (actually, the best interpretation is that fructose and glucose did nothing to proliferation, if their presentation of the statistics is correct).

Now, the kicker, what is the plasma concentration of fructose in most people? It's 8 µM, even in diabetics it's only 12 µM, while plasma glucose in normal people is around 5000µM (doi: 10.2337/diacare.25.2.353 Diabetes Care February 2002 vol. 25 no. 2 353-357, other papers have found diabetics in ketoacidosis to have levels of around 88µM, which dropped to 11µM when their diabetes was controlled [Clin Biochem. 2010 Jan;43(1-2):198-207. Epub 2009 Sep 8.]).

This is probably due to fructose being mainly taken up and metabolised in the liver, but the bottom line is that pancreatic tissue will never see any more than micromolar concentrations of fructose. Even if plasma levels of fructose from dietary sources reached 55 µM (which would be insanely unlikely), it would, on the basis of the results presented in the article (Cancer Res; 70(15) August 1, 2010) do absolutely nothing to cell proliferation (see Fig 1 again). The authors report that pancreatic cancer patients have 2.5 times the plasma levels of fructose of non-cancer patients, but that is still is 100 times less than the 5mM needed to see any difference in proliferation rate (assuming that the results are statistically significant, which they may not be).

There is one tissue that could be exposed to high levels of fructose, and that is the liver, which receives blood flow direct from the gut. However, even high levels of fructose ingestion (4g/kg; about 10 times what you would get from a can of soft drink) produce concentrations of fructose of no more than 1-2 mM in the portal blood (J Am Coll Nutr. 1986;5(5):443-50., Nutr Metab 1971;13:331-338 (DOI: 10.1159/000175352)), still well below the levels where we see some increase in proliferation of pancreatic cancer cells (well, assuming the results were statistically significant, which they may not be; the hepatic cancer cells were not examined for proliferation effects). Even then, the cells exposure at these high levels is brief, at most 2 hours, whereas in the experiments the cells were exposed for 48 hours. So even if you do drink 10 cans of soft drink at one sitting, your liver cells will be unlikely to be exposed to the proliferative levels of fructose.

Put simply, their results do not support their conclusions on prliferation.

1. While the data on metabolism is clear, again these results are in cells exposed to unphysiological concentrations of fructose for 72 hours. This is completely different from what the cells in your body would be exposed to.

2. It is very hard to get rid of glucose from FCS, and if you did the cells wouldn't grow (and actually die at 0 glucose). And you can't get rid of the FCS, for it contains growth factors the cells need to grow as well. Well, there are serum-free media with added growth factors, but they have their own problems. So there are limitations in how they can study this question. Most of my work is done in cancer cell lines (PC-12 and SHY-5Y amongst others, so I am acutely aware of both the strengths and limitations of tissue culture.

Sunday, August 08, 2010

A Triangle in the Sky

Well, the massing of Venus, Mars and Saturn was completely rained out. Here's a shot from August the 7th, which was much frustrated by cloud (hence no shot with Mercury in it). Venus, Mars and Saturn still make a nice triangle though. Note Venus casting a glow on the clouds.

On the Astronomy Trail in Copenhagen - The Rundetaarn

Left, a statue of Tycho Brahe (with nose), outside the Rundetaarn (Round Tower). Right, a painting in the University of Copenhagen main hall, showing Tycho Brahe receiving a Danish king (Fredrick II?) at his observatory in Copenhagen (the Watermill Tower).

Denmark has an important place in the history of astronomy, it's most famous astronomical son is Tycho Brahe, and his observatory at Uranienborg was a powerhouse of astronomical observation. Other famous astronomers in Denmark were Longomontanus (a collaborator with Brahe) and Rømer (who was the first to get a decent value for the speed of light).

A highly visible sign of Denmark's astronomical history is the Rundetaarn, an observatory built between 1637 and 1642 by King Christian IV. Tycho Brahe had died well before its completion (1601), but was undoubtedly involved in it's getting it built in the first place.

Tycho's collaborator Longomontanus was the observatories first director. The left-hand image is a view of the Rundetaarn from downtown Copenhagen. The image on the right is a a more detailed view of the tower. With Christian IV's rebus on it in gold. The Rundetaarm had everything an astronomer needed, an excellent observatory, a first class library, a students church and not one but two privvies, one on the observatory level. When you have to climb hundreds of stairs and a wired winding ramp to go outside and get relief, and observatory level privvie is luxury indeed.

Right hand image, the steep windy steps up the the observatory level. Left hand image, part of the spectacular view of Copenhagen from the observatory level. The observatory still functions, making the Rundetaarn the oldest functioning observatory in Europe.

Left image, me in one of the little niches (who knows what they were used for) on the long, windy ramp to the steep windy stairs. Right image, the observatory dome on the top.

I wandered past the Rundetaarn several times while in Copenhagen, as it is in the heart of the old city between two big Metro stations, and as the Metro was under maintainance we often had to walk to the bus connection that was taking over the Metros duties, this walk took us past the Rundetaarn.

The first time I went past, I was stunned, as I had no idea this was here. The lead up to the conference was a little hectic, and I didn't investigate tourist possibilities before I ended up in the city itself. Of course, the first time I encountered it the tower was shutting for the night, and it was only at the end of the trip that I could get away from the conference early enough to get in and have a look (the conference ran from 8:30 am to 6:15 pm every day, and was chock full).

The experience was fascinating. If you used a bit of imagination, you could transport yourself back to the 1600's as an early astronomer, peering out over a torch-lit city. There were lots of hstorical documents to inspect on the way up too. A hint, when visiting the twoer DON'T try and climb it in high-heeled shoes.

This is the planetarium mounted in the Rundetaarn.It only dates from 1928, but is a wonderful 3 dimensional model of the solar system as understood at that time (no Pluto).

It replaced an older one that was installed in 1740. This one showed both the Copernican sun-centric system along with Tycho's geocentric system. I wish the replacement had duplicated the original.

Carnival of Space #165 is here.

Carnival of Space #165 is now up at Cumbrian Skies. Aside from a fantastic series of 3D images of Martian Landscapes (bring your red-blue glasses), there is an interesting take on alien life, mysterious gamma ray bursts, habital zones around stars, the Venera missions and much much more. head on over and have a read.

Friday, August 06, 2010

Massing of Venus, Saturn and Mars, August 8

Evening sky looking North-west as seen from Adelaide at 7:00 pm on Sunday August 8. Mercury is below Saturn, Venus and Mars. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

The planetary dance continues. Saturn and Venus are at their closest on Sunday, August 8, forming a tiangle with Mars above. Below, Mercury is clearly visible in the late twilight/early evening sky.

Keep watching, on Thursday the 12th the crescent Moon visit Mercy, then on the 13th it visits Venus, as Venus and Mars draw closer together.